Room and area disinfection utilizing pulsed light

ABSTRACT

Room and/or area disinfection apparatuses are provided which generate pulses of germicidal light at a frequency greater than 3 Hz and project the pulses of light exterior to the disinfection apparatuses. In some cases, the apparatuses include an occupancy sensor for determining presence of an individual in a region extending at least 1.0 meter from the disinfection apparatus and processor executable program instructions for inhibiting and terminating the generation of light from the light source upon the occupancy sensor detecting presence of an individual. In addition or alternatively, the apparatuses may include wheels to affect portability of the apparatus. In some cases, the apparatuses may additionally or alternatively include an actuator for moving the light source relative to a support structure of the disinfection apparatus and processor executable program instructions for activating the actuator while the light source is emitting light.

PRIORITY CLAIM

This application is a continuation of pending U.S. patent applicationSer. No. 15/989,394 filed May 25, 2018, which is a divisional of pendingU.S. patent application Ser. No. 15/454,158 filed Mar. 9, 2017, which isa continuation of International Patent Application No. PCT/US2015/051010filed Sep. 18, 2015, which designates the United States and claimspriority to U.S. Provisional Patent Application No. 62/052,036, filedSep. 18, 2014.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention generally relates to light disinfection systems andmethods and, more specifically to, room and area disinfection systemsand methods utilizing pulsed light with modulated power flux and lightsystems with visible light compensation between pulses.

2. Description of the Related Art

The following descriptions and examples are not admitted to be prior artby virtue of their inclusion within this section.

Pulsed light sources are used in a variety of applications to generaterecurrent pulses of ultraviolet (UV) light. Examples of applicationsinclude but are not limited to polymer curing, food sterilization, fluidand object disinfection, and room/area decontamination. Area/roomdisinfection, in particular, is increasingly becoming an application ofinterest as pulsed UV light as been shown to significantly reduce thenumber of pathogenic microorganisms in an area/room in a short period oftime. In particular, pulsed UV light has been shown to deactivate and,in some cases, kill microorganisms on objects and surfaces in aroom/area at distances within approximately 3 meters from a UV lightsource, depending on factors such as reflectivity and complexity ofobjects in the room. In addition, pulsed UV light has been shown toreduce the number of pathogenic microorganisms within a room/area to alevel considered much less harmful to human health in less thanapproximately 5 minutes. Examples of area/room disinfection applicationsare those used in hospitals and those used in agricultural operations,such as for breeding and/or farming animals.

Many studies suggest germicidal efficacy for microorganism deactivationis chiefly due to the dose of ultraviolet electromagnetic radiationsubtype C (UVC) light applied as well as efficacy in the ultravioletelectromagnetic radiation subtype B (UVB), or the dose of energy withinthe wavelengths of 200 and 320 nanometers. This efficacy is determinedby measuring quantum yield or the number of germicidal actions takingplace per incident photon arriving on a microorganism. Conventional usesof pulsed UV light for UV sanitation of foods generally rely on a highlevel of power per pulse to maximize UVC dose, specifically such thatthe UV light may penetrate into crevices or pores of a food's surface.UV curing and sintering processes also utilize a relatively high levelof power per pulse to maximize UV dose. In other applications whichutilize pulsed UV light to deactivate microorganisms, such as wastewaterdisinfection, a relatively low pulse power may be used but at arelatively high frequency in order to maximize UVC dose for a givenperiod of time. In particular, it is known that pulse power and pulsefrequency each have an effect on UVC dose (however not necessarily aproportional effect), but have an inverse relationship relative to eachother (i.e., the higher the power per pulse, the lower the pulsefrequency and vice versa) and, thus, each can be varied depending on theneeds of the application.

Area/room disinfection applications utilizing pulse UV light, however,induce limitations to which pulse power and pulse frequency may beoptimized. In particular, area/room disinfection processes differ fromother pulsed UV light processes (e.g., curing, sintering, foodsanitization and wastewater treatment processes) in that the UV lightmust be transmitted a relatively long distance (e.g., up to 3 metersfrom a UV source). Due to the inverse-square law, conventional area/roomdisinfection applications utilizing pulsed UV light are generallylimited to using a relatively high level of power per pulse to insure asufficient dose of UVC is transmitted across a room/area. In order tomaximize the UVC dose generated, conventional area/room disinfectionapplications utilizing pulse UV light use a relatively low pulsefrequency (e.g., less than approximately 2 Hz). Despite the compromiseof a relatively low pulse frequency, an area/room disinfection deviceutilizing pulse UV light may be limited in the power level it cangenerate for a pulse due to size limitations of the device. Inparticular, it is often preferred for area/room disinfection devices tobe readily portable such that they may be moved to multiple rooms of abuilding and, thus, the size of the pulsed lamp and the power supplyused to operate it may be limited. Other applications of pulsed UVapplications (e.g., curing, sintering, food sanitization and wastewatertreatment processes) are generally not designed for portability and,thus, are often not limited to the amount of UV light it can generate.

Furthermore, conventional area/room disinfection applications utilizingpulse UV light are generally limited to frequencies less than 2 Hz tothe keep the pulse frequency from potentially inducing seizures (therange of which is generally considered to be 3-60 Hz). In particular,although area/room disinfection utilizing pulsed UV light is typicallyperformed by an automated device in a vacated room/area to limit orprevent exposure of UV light, some rooms/areas may not block the visiblelight generated from the disinfection device. In order to limit exposureof the intensity and/or pulse rate of pulsed light, provisions are oftenused to shield transmission of visible light from the room/area, such asblocking windows of a room or shielding gaps at the top and/or bottom ofa room divider. Such shielding provisions, however, may not block alllight from all areas/rooms and, thus, the pulse frequency of anarea/room disinfection device utilizing pulsed UV light may generally beless limited to 2 Hz or less for safety considerations.

In view of the general knowledge of germicidal efficacy of pulsed UVlight being chiefly dependent on overall UVC dose and the aforementionedrestrictions of area/room disinfection devices which use pulse UV light,the efficiency and efficacy of conventional area/room disinfectiondevices utilizing pulse UV light have been limited. Accordingly, itwould be beneficial to develop methods and systems for increasing theefficiency and efficacy of area/room disinfection devices utilizingpulse UV light.

SUMMARY OF THE INVENTION

The following description of various embodiments of apparatuses is notto be construed in any way as limiting the subject matter of theappended claims.

Embodiments of an apparatus include a germicidal pulsed light sourcearranged within the apparatus such that germicidal light generated fromthe germicidal pulsed light source is projected exterior to theapparatus. The apparatus further includes trigger voltage circuitry forapplying a trigger voltage to the germicidal pulsed light source at aset frequency greater than approximately 3 Hz. In some cases, theapparatus includes an occupancy sensor for determining presence of anindividual in a region extending at least 1.0 meter from thedisinfection apparatus and processor executable program instructions forinhibiting and terminating the generation of light from the germicidalpulsed light source upon the occupancy sensor detecting presence of anindividual. In addition or alternatively, the apparatus may includewheels to affect portability of the apparatus. In other cases, theapparatus may additionally or alternatively include an actuator formoving the germicidal pulsed light source relative to a supportstructure of the disinfection apparatus and processor executable programinstructions for activating the actuator while the germicidal pulsedlight source is emitting light.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to theaccompanying drawings in which:

FIG. 1 illustrates an example of a room/area disinfection device;

FIG. 2 illustrates an example of a cooling system which may be used forthe light sources of the apparatuses disclosed herein;

FIG. 3 illustrates an example of a different room/area disinfectiondevice;

FIGS. 4 and 5 illustrates examples of enclosed spaces;

FIG. 6 illustrates target ranges of energy flux and power flux ofultraviolet light between approximately 200 nm and approximately 320 nmfor a lamp surface and distances 1.0, 2.0 and 3.0 meters away from thelamp;

FIG. 7 illustrates a graph showing disinfection efficacy of fivedifferent trigger voltage frequencies over time at a surfaceapproximately 2 meters away from a germicidal pulsed light source;

FIG. 8 illustrates an example of an apparatus having a germicidal lightsource and a separate visible light source; and

FIG. 9 illustrates a diagram of options for generating light at each oflight sources of the apparatus depicted in FIG. 8.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Methods and apparatuses for disinfecting surfaces are provided whichgenerate pulses of light from germicidal light sources at a frequency ofgreater than approximately 3 Hz. In particular, methods and apparatusesare provided which generate pulses of ultraviolet light at a frequencygreater than approximately 20 Hz with significantly lower power fluxthan pulses of light generated from conventional disinfectionapparatuses. Such methods and apparatuses are described in more detailbelow in reference to FIGS. 1-7. In addition, methods and apparatusesare provided which generate pulses of light including ultraviolet lightand visible light from one lamp at a frequency between approximately 3Hz and approximately 60 Hz and further emit visible light from aseparate lamp to insure visible light emitted by the two lamps producesa continuous stream of visible light or a collective stream of visiblelight pulsed at a frequency greater than 50 Hz. Such methods andapparatuses are described in more detail below in reference to FIGS. 8and 9. As will be set forth in more detail below, the apparatuses andcomponents described herein are not limited to the depictions in thedrawings. Several other configurations of apparatuses and components maybe considered. Furthermore, it is noted that the drawings are notnecessarily drawn to scale.

Each of the methods and apparatuses described herein includes use of agermicidal light source. The term “germicidal light source” as usedherein refers to a light source designed to generate and emit germicidallight, i.e., light which is capable of deactivating or killingmicroorganisms, particularly disease carrying and/or disease producingmicroorganisms (a.k.a., germs). The term “kill,” as used herein, meansto cause the death of an organism. The term “deactivate,” as usedherein, means to render an organism unable to reproduce without killing.The germicidal light sources considered for the methods and apparatusesdescribed herein may be configured to generate any type of germicidallight. Ranges of light which are known to be germicidal includeultraviolet light between approximately 200 nm and approximately 320 nmand visible violet-blue light (also known as high-intensitynarrow-spectrum (HINS) light) between approximately 400 nm andapproximately 470 nm. Examples of germicidal light sources which may beconfigured to generate ultraviolet light and/or HINS light includedischarge lamps, light emitting diode (LED) solid state devices, andexcimer lasers. HINS lamps are generally constructed of LEDs. In somecases, the germicidal light sources considered for the methods andapparatuses described herein may be polychromatic in that they generatelight of more than one wavelength. In some further embodiments, thegermicidal light sources considered for the methods and apparatusesdescribed herein may generate light which is not germicidal, such as butnot limited to visible light, but such capability will not deter fromthe reference of the light sources being germicidal.

In any case, the germicidal light sources considered for the apparatusesdescribed herein may be of any size and shape, depending on the designspecifications of the apparatuses. Lamps having exterior surfacesbetween approximately 50 cm² and approximately 250 cm² may beparticularly appropriate for the methods and apparatuses describedherein since they are directed to room/area disinfection processes, butlamps with smaller or larger exterior surfaces may be used.

As noted above, the methods and apparatuses described herein generaterecurrent pulses of light from germicidal light sources at frequenciesgreater than approximately 3 Hz. As such, the methods and apparatusdescribed herein include configurations by which to generate pulses oflight from germicidal light sources. For example, the methods andapparatuses described herein may utilize a pulsed germicidal lightsource and applicable circuitry for triggering a stored amount ofelectrical energy for a set pulse duration to the pulsed germicidallight source. An example of an apparatus with such a configuration ofcomponents is described in more detail below in reference to FIG. 1. Theterm “pulsed germicidal light source” as used herein refers to a lampwhich is designed to only generate and emit recurrent pulses ofgermicidal light (i.e., it cannot generate and emit continuous streamsof germicidal light). Such lamps differ from “continuous germicidallight sources” which are configured to generate and emit continuousstreams of germicidal light upon application of continuous currentthereto. In some cases, the methods and apparatuses described herein mayutilize a continuous germicidal light source and applicable circuitryfor turning the continuous germicidal light source on and off at a setfrequency such that the continuous germicidal light source may generateand emit recurrent pulses of germicidal light. An example of anapparatus with such a configuration of components is described in moredetail below in reference to FIG. 3. To accommodate both types of lightsources for the methods and apparatuses described herein, the methodsand apparatuses described herein may be referred to as methods,apparatuses, devices or systems which generate recurrent pulses ofgermicidal light.

As noted above, examples of germicidal light sources which may beconfigured to generate ultraviolet light and/or HINS light includedischarge lamps. A discharge lamp as used herein refers to a lamp thatgenerates light by means of an internal electrical discharge betweenelectrodes in a gas. The term encompasses gas-discharge lamps, whichgenerate light by sending an electrical discharge through an ionized gas(i.e., a plasma). The term also encompasses surface-discharge lamps,which generate light by sending an electrical discharge along a surfaceof a dielectric substrate in the presence of a gas, producing a plasmaalong the substrate's surface. As such, the discharge lamps which may beconsidered for the germicidal light sources described herein may includegas-discharge lamps as well as surface-discharge lamps. Discharge lampsmay be further characterized by the type of gas/es employed and thepressure at which they are operated. The discharge lamps which may beconsidered for the methods and apparatuses described herein includethose of low pressure, medium pressure and high intensity. In addition,the gas/es employed may include helium, neon, argon, krypton, xenon,nitrogen, oxygen, hydrogen, water vapor, carbon dioxide, mercury vapor,sodium vapor and any combination thereof. In some embodiments, variousadditives and/or other substances may be included in the gas/es. In anycase, the discharge lamps considered for the germicidal sourcesdescribed herein may include those which generate continuous light andthose which generate recurrent pulses of light, the latter of which areoften referred to as flashtubes or flashlamps.

A commonly used gas-discharge lamp used to produce continuous light is amercury-vapor lamp, which may be considered for some of the germicidalsources described herein. It emits a strong peak of light at 253.7 nm,which is considered particularly applicable for germicidal disinfectionand, thus, is commonly referenced for ultraviolet germicidal irradiation(UVGI). A commonly used flashlamp which may be considered for thedisinfection apparatuses described herein is a xenon flashtube. A xenonflashtube generates a broad spectrum of light from ultraviolet toinfrared (including visible light) and, thus, provides ultraviolet lightin the entire spectrum known to the germicidal (i.e., betweenapproximately 200 nm and approximately 320 nm). In addition, a xenonflashtube can provide relatively sufficient intensity at wavelengthranges known to be optimally germicidal (i.e., between approximately 229nm and approximately 231 nm and between approximately 260 nm andapproximately 265 nm). Moreover, a xenon flashtube generates an extremeamount of heat, which can further contribute to the deactivation andkilling of microorganisms.

As noted above, a surface-discharge lamp may also be considered for someof the disinfection apparatuses described herein. Similar to a xenonflashtube, a surface-discharge lamp produces ultraviolet light in theentire spectrum known to the germicidal (i.e., between approximately 200nm and approximately 320 nm). In contrast, however, surface-dischargelamps operate at higher energy levels per pulse and, thus, greater UVefficiency, as well as offer longer lamp life as compared to xenonflashtubes. It is noted that the aforementioned descriptions andcomparisons of a mercury-vapor lamp, a xenon flashlamp and a surfacedischarge lamp in no way restrict the disinfection apparatuses describedherein to include such lamps. Rather, the aforementioned descriptionsand comparisons are merely provided to offer factors which one skilledin the art may contemplate when selecting a discharge lamp for adisinfection apparatus, particularly depending on the objective andapplication of the apparatus.

Turning to the drawings, FIG. 1 illustrates an example of an apparatusconfigured to generate pulses of ultraviolet light at frequenciesgreater than approximately 20 Hz with significantly lower power fluxrelative to pulses of light generated from conventional disinfectionapparatuses. In particular, FIG. 1 shows apparatus 20 with base 24 witha number of components to affect such functionalities for germicidalpulsed light source 22, the specifics of which will be described in moredetail below. More specifically, FIG. 1 illustrates base 24 includingenergy storage element/s 26, trigger voltage circuitry 28, powercircuitry 30, pulse duration circuitry 32, program instructions 34,processor 36, and optional battery 38. As further shown in FIG. 1,apparatus 20 may include additional components, such as remote userinterface 40, power cord 42, wheels 44 and occupancy sensor 46. It isnoted that placement of the noted components are not restricted to thedepiction of FIG. 1, but rather the components may be disposed at anylocation to affect the functionality they impart to apparatus 20. Assuch, the components shown in base 24 in FIG. 1 need not be disposedwithin base 24 necessarily. Furthermore, power cord 42, wheels 44 andoccupancy sensor 46 may be disposed at other locations of apparatus 20.In any case, apparatus 20 may include additional or alternativecomponents that are not shown in FIG. 1, such as but not limited to auser interface on the apparatus (in addition or alternative to remoteuser interface 40), a handle to aid in portability of the apparatus, apower socket inlet (in addition or alternative to power cord 42) and/oradditional sensors, such as additional occupancy sensors and lightsensors.

Regardless of their location within apparatus 20, the electricalcomponents of apparatus 20 are in general in electrical communicationwith each other via wired and/or wireless connections to affectoperations of the apparatus. For instance, power circuitry 30 iselectrically coupled to energy storage element/s 26, trigger voltagecircuitry 28, and pulse duration circuitry 32 to generate a pulse oflight from germicidal pulsed light source 22 and power circuitry 30 isfurther electrically coupled to processor 36, remote user interface 40(and/or a user interface on the apparatus), and occupancy sensor 46 toaffect the commencement and termination of operations of the apparatus.In addition, processor 36 is electrically coupled to programinstructions 34 such that the program instructions may be executed bythe processor and, in addition, processor 30 is electrically coupled toremote user interface 40 (and/or a user interface on the apparatus)and/or any sensors of apparatus 20 to affect operations of germicidalpulsed light source 22 in accordance with program instructions 34. Otherelectrical connections may be included in the apparatus 20 between anyof the noted components and other components of apparatus 20 to affectoperations thereof.

As noted above, apparatus 20 includes a number of components in base 24to affect the generation pulsed light from pulsed germicidal lightsource 22 at a frequency greater than approximately 20 Hz withsignificantly lower power flux relative to pulses of light generatedfrom conventional disinfection apparatuses. In particular, base 24includes trigger voltage circuitry 28 which is configured to apply asufficient voltage at a set frequency by which to activate pulsedgermicidal light source 22 to generate recurrent pulses of light. Inaddition, base 24 includes energy storage element/s 26 and pulseduration circuitry 32 respectively configured to discharge a set amountof stored energy in a set amount of time to pulsed germicidal lightsource 22. The components making up trigger voltage circuitry 28, energystorage element/s 26 and pulse duration circuitry 32 and the operationincurred by such features will generally depend on design of thegermicidal light source. For example, a flashlamp includes one or morecapacitors for energy storage element/s and includes one or moreinductors for its pulse duration circuitry 32. In addition, the triggervoltage in a flashlamp serves to ionize the gas in the flashlamp andcause the capacitor/s to discharge their accumulated energy thereto forthe duration governed by the inductor/s. In any case, the voltage levelsapplied to trigger voltage circuitry 28 and pulse duration circuitry 32as well as to energy storage element/s 26 to accumulate charge thereinmay generally depend on the design specifications (e.g., the desiredpulse frequency, pulse duration, pulse intensity, exterior surface areaof pulsed germicidal light source 22, among other parameters known tothose skilled in the art of pulsed light source design). Example rangesare described in reference to FIG. 6 regarding the desired power fluxesshown therein.

As noted above, apparatus 20 configured to generate pulses ofultraviolet light at frequencies greater than approximately 20 Hz. Suchfunctionality is governed by trigger voltage circuitry 28. Inparticular, trigger voltage circuitry 28 may be configured to apply atrigger voltage at a frequency greater than 20 Hz to germicidal pulsedlight source 22 and, in some applications, frequencies greater than 40Hz, greater than 50 Hz or even greater than 55 Hz may be particularlysuitable. In other embodiments, trigger voltage circuitry 28 may beconfigured to apply a trigger voltage at a frequency greater than 60 Hzand, particularly between approximately 60 Hz and approximately 100 Hzto germicidal pulsed light source 22. In particular, it may beadvantageous for trigger voltage circuitry 28 to apply a trigger voltageto germicidal pulsed light source 22 at a frequency above the safetythreshold for inducing seizures (which is generally considered to beabout 60 Hz). In yet further embodiments, it may be advantageous fortrigger voltage circuitry 28 to apply a trigger voltage to germicidalpulsed light source 22 at a frequency slightly above the seizureinducing threshold for safety purposes (e.g., in light of variability ofvoltage draw from a mains alternating current power supply of abuilding), such as a frequency of 65 Hz or greater.

In some cases, it may be advantageous for trigger voltage circuitry 28to apply a trigger voltage to germicidal pulsed light source 22 at afrequency at which light appears to be continuous to the human eye. Forexample, light pulsed at frequencies of 60 Hz and greater wherein thepulse durations are approximately 25 microseconds appears to becontinuous to the human eye. It is believed that the minimum frequencylevel to invoke the appearance of continuous light to the human eyevaries with the duration of the pulses, specifically the minimumfrequency level increases when pulse durations decrease and vice versa.Thus, the frequency level to set a trigger voltage at to induce theappearance of continuous light to the human eye may vary amongapplications, depending on the design specifications of the germicidalpulsed light source, particularly the pulse duration. In yet furtherembodiments, a frequency range of 60 Hz to 90 Hz may be beneficial formaximizing UVC dose from a germicidal pulsed light source within a givenperiod without causing excessive operational stress on the dischargelamp. It is noted that for the development of the ideas provided herein,trigger voltages of 67 Hz were repeatedly tested, but the scope of theideas disclosed herein should not be limited to such a frequency. Otherexemplary ranges of frequencies greater than 20 Hz may be considered,including those which exceed 100 Hz.

As noted above, apparatus 20 may include optional battery 38 connectedto the power supply circuitry, which may be used for supplying power toone or more components of the apparatus. It is noted, however, giventheir large power requirements, it is generally advantageous to powergermicidal pulsed light source 22, energy storage elements 26, triggervoltage circuitry 28 and pulse duration circuitry 32 from a mainsalternating current power supply of a building in which the apparatus isarranged via a power cord comprising the apparatus or connected to apower socket inlet of the apparatus. In such cases, the power supplycircuitry may include a step-up transformer for increasing alternatingcurrent received via the power cord and/or the power socket inlet andfurther a rectifier for converting alternating current received from thestep-up transformer into direct current for operation of the germicidalpulsed light source. It is contemplated, however, that continuousgermicidal light sources of some apparatus may be powered by a batterysince they have much lower power requirements. In such cases, it may bepossible for the apparatus to be void of a power cord and/or a powersocket inlet for connecting to a mains alternating current power supplyof a building.

In some cases, pulsed germicidal light sources may generate a lot heatand, thus, may need to be cooled during operation. The type of coolingsystem may include convection cooling, forced air/gas cooling or liquidcooling, the selection of which may generally depend on the designcharacteristics of the apparatus, particularly the power flux it isconfigured to generate. An example of a forced air system is illustratedin FIG. 2 as an example for pulsed germicidal light source 22 in FIG. 1.In particular, FIG. 2 illustrates pulsed germicidal light source 22disposed within circumjacent barrier 50 between air inlet 52 and airoutlet 54 with air inlet 52 having an air moving device 56 disposed inproximity thereto, in effect forming plenum 58 around pulsed germicidallight source 22. Circumjacent barrier 50 is made of a materialtransparent to the germicidal light such that germicidal light generatedby pulsed germicidal light source 22 may be transmitted exterior toapparatus 20.

In some embodiments, circumjacent barrier 50 may include a materialwhich attenuates some or all visible light generated by pulsedgermicidal light source 22 and or apparatus may include additionalcircumjacent barrier of such material surrounding circumjacent barrier50. The inclusion of such a material in either of such cases may bebeneficial when the intensity of visible light generated by pulsedgermicidal light source 22 is very high, particularly when it is causesvisual discomfort or distraction upon exposure. In other cases, however,when the intensity of visible light generated by pulsed germicidal lightsource 22 is relatively low, it may be advantageous to omit barrieraround pulsed germicidal light source 22 that attenuates visible light.In particular, a visible light filter could reduce the intensity oflight in other ranges, such as a germicidal range and, thus, reduce thepower flux of the germicidal light emitted from apparatus 20.

In any case, air moving device 56 draws air into plenum 58 through airinlet 52 and discharges through air outlet 54. In an alternativeembodiment, air moving device 56 may be arranged in proximity to airoutlet 54. In any case, air moving device 56 may be any deviceconfigured to cause air to flow, including but not limited to a fan or aturbine. In cases in which a turbine is used in the apparatusesdescribed herein, the turbine may be used to supply power to one or morecomponents of the apparatuses, including any of the components describedherein or a battery of the apparatus. In any case, air inlet 52 mayinclude a filter to remove particular matter from an incoming airstream.

In some cases, air outlet 54 may include an ozone reducing device 60,such as a carbon filter or a device which produces free radicalscatalysts that covert ozone to diatomic oxygen. In particular, ozonemay, in some cases, be created as a byproduct from the use of pulsedgermicidal light source 22, specifically if the lamp generatesultraviolet light of wavelengths shorter than approximately 240 nm sincesuch a spectrum of UV light causes oxygen atoms of oxygen molecules todissociate, starting the ozone generation process. Ozone is a knownhealth and air quality hazard and, thus, the release of it by devices isregulated. It is also known that ozone is an effective germicidal agentand deodorizer and, thus, if the amount of ozone to be generated bypulsed germicidal light source 22 is lower than the local/regionalexposure limits for ozone, it may be beneficial to exclude an ozonereducing device 60 from air outlet 56. In yet other cases, air outlet 56may have a portion with an ozone reducing device and a portion withoutan ozone reducing device and further an air flow regulator torespectively route air through the different portions depending onoperating parameters and/or modes of disinfection processes employed byapparatus 20. Examples of air outlets having such features are describedin more detail in U.S. application Ser. No. 14/790,827 filed Jul. 2,2015, which is incorporated herein by reference as if set forth fullyherein.

Regardless of whether apparatus 20 includes an ozone reducing device,apparatus 20 may, in some cases, include reflector at an elevation abovepulsed germicidal light source 22 to redirect light emitted from pulsedgermicidal light source 22 downwardly. In particular, the methods andapparatuses described herein may be particularly specific to room/areadisinfection and, thus, it may be advantageous to include a reflectorfor redirecting light from pulsed germicidal light source 22 to a regionexterior to the apparatus 20 and which is between approximately 2 feetand approximately 4 feet from a floor of a room in which apparatus 20 isarranged. In general, the region between approximately 2 feet andapproximately 4 feet from a floor of a room is considered a “high touch”region of a room since objects of frequent use are generally placed insuch a region. Examples of objects typically found in a high touch zoneof a room include but are not limited to desktops, keyboards,telephones, chairs, door and cabinet handles, light switches and sinks.Examples of objects in high touch zones of hospital rooms additionallyor alternatively include beds, bedside tables, tray tables andintravenous stands. Due to such a region being considered a high touchzone, it is generally considered the area of highest probability to comein contact with germs and some studies indicate that the high touch zonemay be the area having the highest concentration of germs.

FIG. 2 illustrates an example of a reflector for apparatus 20 disposedat an elevation above pulsed germicidal light source 22 for redirectinglight emitted from the light source downwardly to a region which isbetween approximately 2 feet and approximately 4 feet from a floor of aroom in which apparatus 20 is arranged, specifically annular reflector62 around air outlet 54. Other configurations (e.g., size, shape, angle,distance from pulsed germicidal light source 22) of reflectors may beused and/or reflectors may be arranged at other locations withinapparatus 20 to aid in distributing light to areas of interest in aroom, particularly distances 1 to 3 meters away from apparatus 20.Examples of area/room disinfection apparatuses having reflectors withsuch function are disclosed in U.S. application Ser. No. 13/706,926filed Dec. 6, 2012 and Ser. No. 13/708,208 filed Dec. 7, 2012 as well asInternational Patent Application No. PCT/US2014/059698 filed Oct. 8,2014, all of which are incorporated herein by reference as if set forthfully herein.

Another configuration which characterizes the apparatuses describedherein to specifically affect room/area disinfection is that thegermicidal light source arranged within the apparatus such thatgermicidal light generated from the germicidal light source is projectedexterior to the apparatus. In some cases, a germicidal light source maybe arranged lengthwise substantially perpendicular to a horizontal planeof a support structure supporting one end of the light source. Inaddition or alternatively, the apparatus may be void of an opaquecomponent 360° around an elongated portion of the germicidal lightsource such that light emitted from the germicidal light sourceencircles the apparatus, such as shown for pulsed germicidal lightsource 22 in FIGS. 1 and 22. Furthermore, some of apparatuses describedherein may include an actuator for moving its germicidal light sourcewithin the apparatus (such as with respect to a support structuresupporting the light source) to aid in the distribution of light in aroom or area. In such regard, the methods described herein may includeautomatically moving a germicidal light source within apparatus whilethe germicidal light source is emitting light and/or in between pulsesof light. Another feature which characterizes the apparatuses describedherein to specifically affect room/area disinfection is have anoccupancy sensor, such as a motion sensor, a thermal sensor or a photorecognition sensor. In such cases, the methods described herein mayinclude inhibiting and/or terminating the generation of pulses of lightfrom the germicidal light source upon making a detection which isindicative of occupancy within the area/room in which the apparatus isarranged.

Yet other features which may be included in the apparatuses describedherein to specifically affect room/area disinfection are those thataffect portability of the apparatus, such as wheels and/or a handle. Inparticular, is often preferred for area/room disinfection devices to bereadily portable such that they may be moved to multiple rooms of abuilding. In some embodiments, the apparatuses described herein mayinclude processor executable program instructions for receiving dataregarding characteristics of an enclosed space in which the disinfectionapparatus is to be operated. In general, the phrase “characteristics ofan enclosed space” as used herein refers to physical attributes as wellas non-physical attributes of an enclosed space. Non-physical attributesof an enclosed space include but are not necessarily limited toidentifiers used to reference an enclosed space (e.g., room numberand/or room name) and occupancy information regarding an enclosed space(e.g., infection information of a patient previously occupying the spaceor a patient scheduled to occupy the space). Physical attributes of anenclosed space include but are not necessarily limited to size and/ordimensions of the enclosed space and/or the number, size, distances,locations, reflectivity and/or identification of surfaces, objectsand/or items within the enclosed space. In some cases, a physicalattribute of an enclosed space may be the identification of one or morepathological organisms and, sometimes further the number orconcentration of such organism/s in the enclosed space, in a particularregion of the enclosed space, or on a particular surface in the enclosedspace.

In any case, the data received regarding the characteristics of theenclosed space in which the disinfection apparatus is to be operated maybe utilized in a number of manners, including but not limited torecordation or reporting purposes or setting one or more operationalparameters of the apparatus. In some embodiments, the apparatusesdescribed herein may include a means for automatically moving theapparatus. In some such cases, the apparatus may include programinstructions to move the apparatus along a predetermined route. Inaddition or alternatively the apparatus may include program instructionsto move the apparatus in accordance with room characteristics of a roomwhich have been analyzed via one or more sensors of the apparatus,including sensors for mapping or modeling an area/room. Examples ofarea/room disinfection apparatuses with some of the aforementionedprogram instructions are disclosed in U.S. application Ser. No.13/706,926 filed Dec. 6, 2012, which is incorporated by reference as ifset forth fully herein.

Other configurations which may aid in facilitating the apparatuses forroom/area disinfection may be considered. More specifically, theapparatuses described herein may be configured (with the configurationsnoted above or with other configurations) to expose areas and rooms aswell as objects as a whole to germicidal light and, thus, may bespecifically configured to distribute light in a spacious manner to anambient of a room in which the disinfection apparatus is arranged. Inaddition, the apparatuses described herein may be configured todistribute germicidal light to surfaces within a room or area that aregreater than 1 meter or even 2 or 3 meters from a germicidal flashlamp.The apparatuses may be of any shape, size, or configuration in which toachieve such objectives. Examples of area/room disinfection apparatusesare disclosed in U.S. application Ser. No. 13/706,926 filed Dec. 6, 2012and Ser. No. 13/708,208 filed Dec. 7, 2012; as well as InternationalPatent Application No. PCT/US2014/059698 filed Oct. 8, 2014, all ofwhich are incorporated herein by reference as if set forth fully herein.Other configurations of area/room disinfection apparatuses, however, maybe employed for apparatuses described herein.

As used herein, the term “room/area disinfection” refers to thecleansing of a space which is suitable for human occupancy so as todeactivate, destroy or prevent the growth of disease-carryingmicroorganisms in the area. The phrase “a space which is suitable forhuman occupancy” as used herein refers to a space in which an adulthuman being of average size may comfortably occupy for at least a periodof time to eat, sleep, work, lounge, partake in an activity, or completea task therein. In some cases, spaces suitable for human occupancy maybe bounded and include a door for entering and exiting the room. Inother cases, a space suitable for human occupancy may be an area withindeterminate boundaries. Examples of spaces which are suitable forhuman occupancy include but are not limited to single patient rooms,multiple occupancy patient rooms, bathrooms, walk-in closets, hallways,bedrooms, offices, operating rooms, patient examination rooms, waitingand/or lounging areas and nursing stations. As used herein, the term“enclosed space” refers to an area having its boundaries defined bybarriers blocking a vast majority or all germicidal light transmissionexterior to the area.

Examples of enclosed spaces suitable for human occupancy in which theapparatuses described herein may be used to conduct area/roomdisinfection processes are shown in FIGS. 4 and 5. In particular, FIG. 4illustrates operating or patient room 80 having door 82 closed andhaving disinfection apparatus 84 disposed therein. In such cases, thewalls and windows (if applicable) of room 80 as well as door 82 serve asbarriers defining the boundaries of room 80 to form an enclosed spacesuitable for human occupancy. Although door 82 is shut to consider thespace enclosed, germicidal light may be transmitted around the peripheryof the door if it is not sealed. In such cases, a vast majority ofgermicidal light transmission is blocked from being transmitted exteriorto room 80 and, thus, is considered an enclosed space.

FIG. 5, on the other hand, illustrates multi-occupancy room 86 havingdoor 88 open but including partitioned area 90 sectioned off by roomdivider 92, such as a cubicle curtain. As shown, partitioned area 90includes one of the plurality of disinfection apparatus 94. In suchcases, the walls and windows (if applicable) of room 86 in partitionedarea 90 as well as room divider 92 serve as barriers defining theboundaries of partitioned area 90 to form an enclosed space suitable forhuman occupancy. It is appreciated that room divider 92 may not fullyextend to the walls, ceiling, and/or the floor of room 86 and, thus,germicidal light may be transmitted around room divider 92. In suchcases, a vast majority of germicidal light transmission is blocked frombeing transmitted exterior to partitioned area 90 and, thus, isconsidered an enclosed space. In general, disinfection apparatuses 84and 94 shown in FIGS. 4 and 5 may include any of the apparatusesdisclosed herein. It is noted that the number, size, placement, andportability of disinfection apparatuses 84 and 94 are not exclusive tothe respective embodiments of FIGS. 4 and 5 showing a room as enclosedspace and a partitioned section of a room as an enclosed space. Inparticular, any of the apparatuses disclosed herein may be employed inany enclosed space which is suitable for human occupancy.

As noted above, apparatus 20 in FIG. 1 is an example of an apparatuswhich may be used to generate pulses of ultraviolet light at frequenciesgreater than approximately 20 Hz with significantly lower power fluxrelative to pulses of light generated from conventional disinfectionapparatuses. Several other configurations of apparatuses may beconsidered for such functionalities, one of which is depicted in FIG. 3.In particular, FIG. 3 illustrates apparatus 70 including a plurality ofgermicidal light sources 72 arranged in frame 74. In some cases, thebackside of apparatus 70 may include a backside panel spanning the arealdimension of frame 74 to prevent emission of germicide from the backsideof apparatus 70. In other embodiments, the backside of apparatus 70 maybe open such that light may be emitted on either side of the apparatus.In any case, apparatus 70 may be considered for use for area/roomdisinfection. In some embodiments, apparatus 70 may be mountable on awall or a ceiling. Alternatively, apparatus 70 may be a standalonedevice.

In any case, the dimensions and shape of frame 74 may vary from thatdepicted in FIG. 3. More specifically, frame 74 is not limited to beingrectangular and/or having the relatively thin sidewalls depicted in FIG.3. Furthermore, the orientation of apparatus 70 is not limited to itslongitudinal dimension being horizontal. Moreover, apparatus 70 is notlimited to having multiple cylindrical germicidal light sourcesorientated in the manner shown in FIG. 3. Rather, apparatus 70 mayinclude any number, size, shape and orientation of germicidal lightsources. Moreover, germicidal light sources 72 may include the same typeof germicidal light source or different types of germicidal lightsources. In some cases, apparatus 70 may be configured to move one ormore of germicidal sources 72 to extend out of frame 74 to enhancedistribution of germicide/s generated therefrom into an ambient of theapparatus. An example configuration to offer such an option may includeretractable tracks extending out from frame 74 in alignment withgermicidal sources 72, along which the germicidal sources may be movedmanually or by an actuator.

In any case, apparatus 70 may include any of the features described inreference to apparatus 20 of FIG. 1. In particular, apparatus 70 mayinclude one or more of energy storage element/s 26, trigger voltagecircuitry 28, power circuitry 30, pulse duration circuitry 32, programinstructions 34, processor 36, optional battery 38, remote userinterface 40, power cord 42, wheels 44, occupancy sensor 46, a userinterface on the apparatus (in addition or alternative to remote userinterface 40), a handle to aid in portability of the apparatus, a powersocket inlet (in addition or alternative to power cord 42) and/oradditional sensors, such as additional occupancy sensors and lightsensors. Such features are not shown in apparatus 70 to simplify thedrawing in FIG. 3. Furthermore, such features are not described inreference to apparatus 70 for the sake of brevity.

Furthermore, apparatus 70 may include any of the cooling system featuresdescribed in reference to apparatus 20 of FIG. 1 and the specificembodiment of the forced air cooling system described in reference toFIG. 2. For example, although not shown, apparatus 70 may include anynumber of air moving devices, air inlets, and air outlets. In addition,the front side and possibly the back side of apparatus 70 may includepanels within frame 74 which are transparent to ultraviolet light and,if desired, also opaque to visible light. In general, the air movingdevice/s, air inlet/s, and air outlet/s may be arranged within any sideof frame 74. In addition or alternatively, air moving device/s may bearranged internal to frame 74, particularly but not necessarily inalignment with air inlet/s or air outlet/s within the frame. In anycase, air moving device/s may be arranged upstream or downstream of anair stream induced through frame 44. In some cases, apparatus 70 mayinclude an air moving device disposed at one end of at least one ofgermicidal sources 72 (and, in some cases, include an air moving devicedisposed at the end of each of germicidal sources 72) to induce an airstream which flows substantially parallel with the longitudinaldimension of the germicidal light sources, such as described forgermicidal source 22 in reference to FIG. 2. In other cases, apparatus70 may have air moving devices arranged to induce an air stream thattraverses germicidal sources 72.

As noted above, however, the apparatuses described herein may includeseveral different configurations and, thus, apparatus 70 may, in somecases, include different features than apparatus 20 of FIG. 1. Forexample, germicidal light sources 72 may not be pulsed germicidal lightsources, but rather continuous germicidal light sources and, thus,apparatus 70 may not include energy storage element/s 26, triggervoltage circuitry 28, and pulse duration circuitry 32. Instead,apparatus 70 may include circuitry for turning the continuous germicidallight sources on and off at a set frequency (e.g., >20 Hz) such that thecontinuous germicidal light sources may generate and emit recurrentpulses of germicidal light.

As noted above, FIGS. 1 and 3 depict examples of apparatuses configuredto generate pulses of ultraviolet light at frequencies greater thanapproximately 20 Hz with significantly lower power flux relative topulses of light generated from conventional disinfection apparatuses.The term “power flux”, as used herein, refers to the transmission rateof radiant energy at a given surface per unit area. Synonymous terms forpower flux include “irradiance”, “power density” and “radiationintensity” and, thus, the terms may be used interchangeably herein. Theterm “energy flux”, as used herein, refers to the amount of radiantenergy at a given surface per unit area. A synonymous term for energyflux is “radiant energy” and, thus, the terms may be usedinterchangeably herein.

As noted above, many studies suggest germicidal efficacy formicroorganism deactivation is chiefly due to the dose of ultravioletelectromagnetic radiation subtype C (UVC) light applied, or the dose ofenergy within the wavelengths of 200 and 320 nanometers. In lightthereof, studies directed to analyzing energy requirements forgermicidal efficacy generally focus on the power flux or energy flux ofultraviolet light and, in some cases, the power flux or energy flux ofUVC. In particular, some studies teach that a minimum power flux ofultraviolet radiation is needed to achieve sufficient germicidalefficacy. Other studies teach additional parameters need to be met inaddition to power flux, such as particular ratios of peak, average androot mean square power of ultraviolet radiation and/or a contrivedrelationship correlating energy discharged to the lamp, surface area ofthe lamp and pulse duration. Yet other studies tie in pulse frequencyrequirements in addition to power flux, such as specifying a minimumpulse frequency or a required range of pulse frequency.

For example, U.S. Pat. No. 6,264,802 to Kamrukov et al. teaches applyingUV radiation to liquids, air and surfaces with a radiation intensity ofat least 100 KW/m², a pulse duration between 1 and 1000 microseconds andfurther that the energy discharged to the lamp, surface area of the lampand the pulse duration follow a specified relationship. The patent issilent with regard to what pulse frequencies may be employed. U.S. Pat.No. 5,144,146 to Wekhof teaches different power requirements forpurifying wastewater in that an average power density of UV needs to bemaintained at a value of at least 100 W/m² within the wastewater whilethe UV source is pulsed at frequency of 5 to 100 Hz. It is noted thatthe teaching of maintaining an average power density of UV at a value ofat least 100 W/m² is in reference to the entire operation cycle of thelamp rather than just when UV radiation is delivered from the lamp,which differs from the other power requirement parameters disclosed inthe patent. In particular, U.S. Pat. No. 5,144,146 to Wekhof furtherteaches that the ratio of root mean square power to average powerdelivered by the UV source needs to be in range of 10:1 to 100:1 and theratio of peak power to average power delivered by the UV source needs tobe in the range of 1000:1 to 10,000:1.

As will be described in more detail below, the area/room disinfectionprocesses described herein do not meet any of these prior artrequirements, specifically that processes are conducted withsignificantly lower power fluxes at distances 1.0 meter and farther fromthe disinfection apparatuses. In particular, it was discovered duringthe development of the ideas provided herein that sufficient germicidalefficacy could be obtained with pulses of light generated at frequenciesgreater than approximately 50 Hz and with relatively low power flux,particularly less than 5000 W/m² of UV light in the wavelength range of200 nm to 320 nm at surfaces at least 1.0 meter from the disinfectionapparatuses. As used herein, sufficient germicidal efficacy refers to a2-log or more reduction in bacterial contamination on surfaces.

More specifically, in development of the ideas provided herein,disinfection efficacies of five different frequencies ranging between1.0 Hz and 100 Hz were evaluated at a surface 2.0 meters away from agermicidal pulsed light source, the results of which are depicted inFIG. 7. The lamps used for each of the frequencies were xenon flashlampsconstructed of the same materials, the same surface area and the samefill pressure. In the interest to evaluate any variances induced by thedifferences in frequencies, the cycle times of the disinfectionprocesses for each of the frequencies was the same (i.e., 5 minutes) andthe lamps were conducted at operational parameters that producedcomparable power flux at the lamp surface over that cycle time (i.e.,all light generated at the lamp, not just UV or UVC). To accommodatesuch a power flux, the pulse duration and the amount of energyaccumulated at the capacitor/s for discharge to the lamps for thedisinfection processes conducted at higher frequencies are generallylower than disinfection processes conducted at lower frequencies. Inmaking such adjustments, the higher frequency processes are conductedwith a lower power flux per pulse than the lower frequency processes. Inother words, the transmission rate of radiant energy at a given surfaceper unit area is less for each pulse.

As shown in FIG. 7, disinfection efficacy is substantially similar amongthe five different trigger voltage frequencies for 5 minute disinfectionprocesses. Based on the data obtained for the 5 different frequenciestested, it is apparent that a disinfection process may be modulated bythe varying the amount, duration and frequency of UV light applied to asurface at a given distance without substantially affecting thedisinfection efficacy. More specifically, it has been found that UVlight may be applied at a lower intensity and shorter pulse duration butat a higher frequency at a surface at a given distance for a given cycletime and yield substantially similar germicidal efficacy as compared toprocesses applying higher intensity of UV light at lower doses. Severaltheories are contemplated to explain such findings. One theory involveskeeping the targeted pathogen in a “shocked state,” in which there is apotential for damage. In particular, it is theorized that the longer thepathogen is in a “shocked state,” which is caused by incident photons,the more likely the cell is to be deactivated. In order to acquire thisstate, it is believed that there is a minimum level intensity of UVlight needed, which based on the data obtained was attainable with atleast 100 Hz frequencies. In the interest of efficiency, it isspeculated that higher frequencies of pulsing minimize the amount ofphotons to reach this state, but simultaneously maximize the number of“shock state” events.

A second theory involves overwhelming enzymatic cellular repairmechanisms that aid in photo-repair (i.e., repairing a previouslydeactivated cell). In particular, more frequent photon flux induced byhigher frequency applications could overwhelm cellular repair mechanismsbefore repair can be completed. It is further contemplated that thesetheories can be interrelated, specifically that the tested disinfectionefficacy of the higher frequencies could involve a combination of thetwo. Furthermore, it is conceivable that these theories and/or theresults found in testing the five different aforementioned frequenciescould be limited to inanimate objects and/or nosocomial pathogens.

Moreover, it is speculated that the comparable disinfection efficaciesachieved among the five different pulse frequencies tested with respectto FIG. 7 may be due to an increase in power flux at specificwavelengths that potentially have a higher degree of germicidal effectrelative to other wavelengths in the UVC range as pulse frequency isincreased. In particular, it was discovered during the development ofthe ideas provided herein that a disinfection process that generatespulsed light between 60 Hz and approximately 70 Hz produces greaterpower flux at wavelengths of approximately 230 nm, approximately 248 nmand approximately 261 nm than a disinfection process that generatespulsed light between 1.0 Hz and 2.0 Hz, despite the overall power fluxin the UVC range of the 60-70 Hz disinfection process being lower thanthe power flux generated in the UVC range of the 1.0-2.0 Hz disinfectionprocess. It theorized that the larger peaks at approximately 230 nm,approximately 248 nm and approximately 261 nm may compensate for theoverall lower power flux in the UVC range relative to the 1.0-2.0 Hzprocess lending to comparable disinfection efficacy.

Moreover, it is speculated that the comparable disinfection efficaciesachieved among the five different pulse frequencies tested with respectto FIG. 7 may be due to larger variations of power flux in germicidalranges of light as pulse frequency is increased. In particular, it wasdiscovered during the development of the ideas provided herein that adisinfection process that generates pulsed light between 60 Hz and 70 Hzproduces a larger variation of power flux in the UVC range, specificallybetween 210 nm and 320 nm and, more specifically between approximately225 nm and approximately 265 nm, than a disinfection process thatgenerates pulsed light between 1.0 Hz and 2.0 Hz. It theorized that thelarger variation of power flux may compensate for the overall lowerpower flux in the UVC range relative to the 1.0-2.0 Hz process lendingto comparable disinfection efficacy. In particular, a larger variationof power flux within a spectrum of radiation correlates to atomic lineradiation, which generally corresponds to bound-bound energy statetransitions of the photons. In contrast, a smaller variation of powerflux within a spectrum of radiation correlates to continuum radiation,which generally corresponds to free-bound and free-free energy statetransitions of the photons. In general, photons in bound-bound energystate transitions have a higher amount of energy than photons infree-bound and free-free energy state transitions. It is theorized thatthe higher energy of photons induced by a larger power flux variationsexhibited in the UVC range for the 60-70 Hz disinfection process maycompensate for the overall lower power flux in the UVC range relative tothe 1.0-2.0 Hz process, lending to comparable disinfection efficacybetween the two processes.

Some of the variation of power flux in the UVC range for the 60-70 Hzdisinfection process is due to the large peaks centered at approximately230 nm, approximately 248 nm and approximately 261 nm. In takingintegral of such peaks relative to the integral of the range betweenapproximately 225 nm and approximately 265 nm, an approximation of thedegree of variation across such a range was quantified. In particular,approximately 60% of the power flux in that range was due to the peaksfor the 60-70 Hz process and approximately 50% of the power flux in thatrange is due to the peaks for the 1.0-2.0 Hz process. It is noted thatthe 60-70 Hz process exhibited larger power flux variations across otherwavelength ranges of the ultraviolet spectrum and it is contemplatedthose variations may further contribute to the relatively comparabledisinfection efficacy of the 60-70 Hz process relative to the 1.0-2.0 Hzprocess despite the overall lower power flux in the UVC range for the60-70 Hz process. Moreover, the 60-70 Hz process exhibited a largervariation of power fluxes of visible violet-blue light betweenapproximately 420 nm and approximately 470 nm than the power fluxvariation for the 1.0-2.0 Hz process in the same range and it iscontemplated those larger power flux variations may contribute to therelatively comparable disinfection efficacy of the 60-70 Hz processrelative to the 1.0 Hz process. In particular, visible violet-blue lightbetween approximately 400 nm and approximately 470 nm is known to begermicidal and, thus, the higher variation of power flux in such aregion may aid in germicidal efficacy.

Given the discovery that comparable disinfection efficacies may beobtained at 2.0 meters away from a pulsed light source conducted atpulse frequencies ranging between 1.0 Hz and 100 Hz, it is contemplatedthat a room/area disinfection apparatus can be operated at any pulsefrequency if the parameters of the operation are governed to generate aset power flux of light at the lamp which is known to affect sufficientgermicidal efficacy at a desired distance from the disinfectionapparatus. It is further contemplated that a room/area disinfectionapparatus can be operated at any pulse frequency if a desired power fluxof UVC radiation is known to affect sufficient germicidal efficacy at adesired distance from the disinfection apparatus. In particular, theoperational parameters of the apparatus, such as pulse duration, energydischarged to the lamp and lamp itself (particularly the exteriorsurface of the lamp) may be optimized to achieve the desired power fluxof UVC radiation at the desired pulse frequency.

The disclosure provided herein focuses on ranges of power fluxes ofultraviolet light between approximately 200 nm and approximately 320 nmduring a given pulse which may be used for area/room disinfectionapparatuses operated at frequencies greater than approximately 20 Hz,particularly for sufficient germicidal efficacy at 1.0, 2.0 and 3.0meters away from the apparatus. In particular, FIG. 6 illustratesgermicidal light source 98 of a room/area disinfection apparatus withtarget ranges of energy flux and power flux of ultraviolet light betweenapproximately 200 nm and approximately 320 nm specified for the lampsurface and distances 1.0, 2.0 and 3.0 meters away from the apparatus.The entire room/area disinfection apparatus is not shown in FIG. 6 tosimplify the drawing, but the apparatus may generally include any ofapparatus features and configurations described in reference to FIGS.1-3. It is particularly noted that germicidal light source 98 may be apulsed germicidal light source or may be a continuous germicidal lightsource, wherein the latter embodiment, the room/area disinfectionapparatus includes circuitry to turn the light source on and off topulse light therefrom.

As shown in FIG. 6, target ranges of energy flux of ultraviolet lightbetween approximately 200 nm and approximately 320 nm at the surface ofgermicidal light source 98 may be between approximately 20 J/m² andapproximately 1500 J/m². In addition, the target range of power flux ofultraviolet light between approximately 200 nm and approximately 320 nmat the surface of germicidal light source 98 may be betweenapproximately 0.8 MW/m² and approximately 5.0 MW/m². In more specificembodiments, the energy flux and power flux of ultraviolet light betweenapproximately 200 nm and approximately 320 nm at the surface ofgermicidal light source 98 may be between approximately 20 J/m² andapproximately 500 J/m² and between approximately 0.8 MW/m² andapproximately 1.5 MW/m², respectively. As further shown in FIG. 6,target ranges of energy flux of ultraviolet light between approximately200 nm and approximately 320 nm approximately 1.0 meter from germicidallight source 98 may be between approximately 0.02 J/m² and approximately1.5 J/m². In addition, the target range of power flux of ultravioletlight between approximately 200 nm and approximately 320 nmapproximately 1.0 meter away germicidal light source 98 may be betweenapproximately 800 W/m² and approximately 5000 W/m². In more specificembodiments, the energy flux and power flux of ultraviolet light betweenapproximately 200 nm and approximately 320 nm approximately 1.0 meterfrom germicidal light source 98 may be between approximately 0.02 J/m²and approximately 0.5 J/m² and between approximately 800 W/m² andapproximately 1500 W/m², respectively.

FIG. 6 further shows target ranges of energy flux of ultraviolet lightbetween approximately 200 nm and approximately 320 nm approximately 2.0meter from germicidal light source 98 may be between approximately 6.0μJ/m² and approximately 370 μJ/m². In addition, the target range ofpower flux of ultraviolet light between approximately 200 nm andapproximately 320 nm approximately 2.0 meters from germicidal lightsource 98 may be between approximately 200 W/m² and approximately 1300W/m². In more specific embodiments, the energy flux and power flux ofultraviolet light between approximately 200 nm and approximately 320 nmapproximately 2.0 meters from germicidal light source 98 may be betweenapproximately 6.0 μJ/m² and approximately 250 μJ/m² and betweenapproximately 200 W/m² and approximately 800 W/m², respectively.Moreover, FIG. 6 further shows target ranges of energy flux ofultraviolet light between approximately 200 nm and approximately 320 nmapproximately 3.0 meters from germicidal light source 98 may be betweenapproximately 1.5 μJ/m² and approximately 95 μJ/m². In addition, thetarget range of power flux of ultraviolet light between approximately200 nm and approximately 320 nm approximately 3.0 meters from germicidallight source 98 may be between approximately 50 W/m² and approximately300 W/m². In more specific embodiments, the energy flux and power fluxof ultraviolet light between approximately 200 nm and approximately 320nm approximately 3.0 meters from germicidal light source 98 may bebetween approximately 6.0 μJ/m² and approximately 120 μJ/m² and betweenapproximately 200 W/m² and approximately 600 W/m², respectively.

As noted above, the area/room disinfection processes described herein donot meet any of parameters requirements taught in U.S. Pat. No.6,264,802 to Kamrukov et al., U.S. Pat. No. 5,144,146 to Wekhof, U.S.Application No. US 2008/0150443 to Tipton for operation of germicidalpulsed light sources. In particular, the maximum power flux recited inreference to FIG. 6 for distances 1.0, 2.0 and 3.0 meters from agermicidal light source is 5000 W/m², which is two orders of magnitudelower than the 100 KW/m² minimum power flux requirement taught in U.S.Pat. No. 6,264,802 to Kamrukov et al. Likewise, the average powerdensity of UV light over a cycle time of a disinfection process that isconducted using any of the target power flux ranges noted in FIG. 6 islikely at least two orders of magnitude less than the requirement taughtin U.S. Pat. No. 5,144,146 to Wekhof. In particular, a disinfectionprocess conducted with a pulse frequency between 60 Hz and approximately70 Hz for the development of the ideas provided herein was calculated tohave an average power flux in the UV range over the operation of thedisinfection process of 2.9 W/m², which is two orders of magnitude lowerthan the 100 W/m² minimum power flux requirement taught in U.S. Pat. No.5,144,146 to Wekhof. Furthermore, any disinfection process conductedusing any of the target power flux ranges noted in FIG. 6 likely doesnot meet the ratio of root mean square (RMS) power to average powerrequirement or the ratio of peak power to average power requirement. Forexample, a disinfection process conducted with a pulse frequency between60 and 70 Hz for the development of the ideas herein exhibited a ratioof RMS power to average power of 1.4 and a ratio of peak power toaverage power of 4.2 approximately 1.0 meter from the germicidal lightsource during a given pulse.

For some embodiments, frequencies in the range of 55 Hz to 80 Hz and,particularly 67 Hz, were deemed particularly suitable for thedisinfection processes described herein. In particular, frequencies ofthese values have a higher power per pulse than higher frequencies, and,thus, overall UVC dose of the noted frequencies is greater and UVC doseis substantially greater at larger distances due to the inverse squarelaw. Furthermore, conversion of electrical energy to optical energy atthe frequencies of the noted range is more efficient than higherfrequencies. Moreover, there is less overall loss of energy at thefrequencies of the noted range when dealing with relatively large anglesof incidence and reflection. For room disinfection processes, it isdesirable to maximize the manipulation of light to reach areas that arenot in line of sight of the disinfection source. Although frequencies inthe range of 55 Hz to 80 Hz may be advantageous for several reasons, itis reasonable to consider frequencies greater than 80 Hz or lower than55 Hz for the disinfection processes described herein.

Furthermore, frequencies of 50 Hz and greater exhibited beneficialcharacteristics distinct from the processes conducted at a frequencybetween 1.0 Hz and 2.0 Hz. In particular, the noise of the lightgenerated from frequencies of 50 Hz and greater was substantially lessthan the noise of light generated from the 1.0-2.0 Hz frequency.Furthermore, the visual intensity of the light generated fromfrequencies of 50 Hz and greater was substantially less than theintensity of light generated from the 1.0-2.0 Hz frequency. Further tosuch a regard, it was found in additional testing that the visualintensity of the light generated from frequencies of 50 Hz and greaterwas also substantially less than the intensity of light generated fromthe 1.0-2.0 Hz frequency when a visible light filter was used to blockvisible light emitted from the lamp for the 1.0-2.0 frequency process(and no filter was used on the apparatus for the frequencies of 50 Hzand greater).

Additionally in such testing, it was found that the disinfectionefficacy of a 5 minute cycle time for the 1.0-2.0 Hz frequency processemploying a visible light filter decreased substantially, notably overhalf a log difference, relative to embodiments in which a visible lightfilter was not used on the disinfection apparatus during a 1.0-2.0 Hzprocess. It is believed the decrease in disinfection efficacy was due toa combination of altered spectra of light radiation emitted as well as adecrease in the total UVC dose at the targeted surface. Given a visiblelight filter is generally needed for 1.0-2.0 frequency disinfectionprocesses due to the extreme of visible light generated, there is thepossibility for shorter disinfection cycles (i.e., shorter than 5minutes) for disinfection processes using frequencies of 50 Hz andgreater since a visible light filter may not be needed to attenuatevisual stimuli. Also, an improvement in bulb life may be realized fordisinfection processes using frequencies of 50 Hz and greater due to thelower power flux per pulse employed.

As noted above, it may be advantageous utilize a frequency above thesafety threshold for inducing seizures (which is generally considered tobe about 60 Hz) for the methods and apparatuses described herein, but asfurther noted above, lower frequencies (i.e., frequencies less than 60Hz) may be employed. More specifically, frequencies considered topotentially induce seizures (the range of which is generally consideredto be 3-60 Hz) may be employed within the methods and apparatusesdisclosed herein. In such cases, provisions may be used to shield ormask the generation of visible light from the germicidal light source.For example, the disinfection apparatus may include an optical filterconfigured to attenuate a majority or all visible light generated fromthe germicidal light source. In addition or alternatively, thedisinfection apparatus may include a visible light source distinct fromthe germicidal light source that is used to either mask the visiblelight generated by the germicidal light source or is synchronouslypulsed with pulses of light from the germicidal light source such thatthe collective projection of visible light from the two light sources isgreater than a safety threshold for inducing seizures (such as greaterthan 60 Hz).

FIG. 8 illustrates an example of an apparatus including a germicidallight source and a separate visible light source which may be used insuch a manner. In particular, FIG. 8 illustrates apparatus 100 includinggermicidal light source 102 and visible light source 112. Germicidallight source 102 may include any germicidal light source 102 which isconfigured to generate both germicidal light and visible light. Forexample, germicidal light source 102 may be configured to generategermicidal ultraviolet light and visible light. In addition oralternatively, germicidal light source 102 may be configured to generategermicidal visible violet-blue light. In any case, germicidal lightsource 102 may be pulsed germicidal light source or may be a continuousgermicidal light source. In the latter case, apparatus 100 may includecircuitry for turning the continuous germicidal light source on and offat a set frequency such that recurrent pulses of light may be generatedfrom the continuous germicidal light source.

Visible light source 112 may include any light source 102 which isconfigured to generate visible light, including those which can producecontinuous light and those which produced pulsed light. In some cases,visible light source 112 may additionally generate light which is notvisible. In particular embodiments, visible light source 112 mayadditionally generate germicidal light, such as germicidal ultravioletlight and germicidal visible violet-blue light. In some of such cases,visible light source 112 may generate the same type of light asgermicidal light source 102 and, in further embodiments, may be a lightsource of similar type as germicidal light source 102 (i.e., the lightsources generate light in the same manner). In yet other cases, however,visible light source 112 may not be configured to generate germicidallight. Examples of visible light lamps which may be considered includebut are not limited to LED lamps, fluorescent lamps and any type ofgermicidal light source that produces visible light.

In any case, the visible light generated by visible light source 112 mayhave an average intensity of at least approximately 90% of the averagevisible light intensity projected from the germicidal light source 102or passed through an optical filter surrounding germicidal light source102, if applicable. In some embodiments, the visible light generated byvisible light source 112 may have greater intensity than the visiblelight intensity projected from germicidal light source 102 or passedthrough an optical filter surrounding germicidal light source 102, ifapplicable. For example, in embodiments in which visible light source112 emits continuous light, the intensity of the visible light generatedby visible light source 112 may be at least approximately 150% greaterthan the intensity of the visible light projected from germicidal lightsource 102 or passed through an optical filter surrounding thegermicidal light source, if applicable. Alternatively, in embodiments inwhich visible light source 112 generates pulses of visible light, thevisible light generated by visible light source 112 may have an averageintensity between approximately 90% and approximately 110% of theaverage visible light intensity projected from germicidal light source102 or passed through an optical filter surrounding the germicidal lightsource, if applicable. In general, such intensities may be measured atany given distance from light sources, but it may be particularlysuitable if the noted intensities are measured at a given distance 1.0meter or greater from the light sources and, in some cases, at distances2.0 meters or greater or even 3.0 meters or greater from the lightsources. In this manner, the projection of visible light from visiblelight source 112 may be sufficient to mask or be substantiallyequivalent (i.e., +/−10%) to the projection of visible light fromgermicidal light source 102.

In some particular cases, visible light source 112 may include similardimensional configurations (i.e., shape and size) as germicidal lightsource 102. For example, it may be advantageous to for visible lightsource 112 and germicidal light source 102 to have exterior surfaceareas within approximately 20% of each other. Having such comparablesurface areas may facilitate the light sources to emit a comparableamount of light in addition to the light being of comparable intensity.In some cases, visible light source 112 and germicidal light source 102may have exterior surface areas within approximately 10% of each otheror less. In particular embodiments, visible light source 112 andgermicidal light source 102 may have approximately the same exteriorsurface areas.

In some cases, visible light lamp 112 may be tinted to match thespectrum of visible light generated from the germicidal light source102. In addition or alternatively, it may be advantageous for visiblelight source 112 to be a lamp which uses less power than the germicidallight source 102. In particular, a disinfection process utilizing such avisible light lamp and also utilizing a germicidal light source pulsedat a frequency which light appears to be pulsed to the human eye (e.g.,at frequencies less than 60 Hz) may require less power consumption ascompared to a disinfection process using a germicidal light sourcepulsed at a frequency which light appears to be continuous to the humaneye. Such lower power consumption may be an incentive to use the duallamp process versus a process only utilizing a germicidal light source.

Although not necessarily so limited, apparatus 100 may be a room/areadisinfection apparatus and, thus, germicidal light source 102 andvisible light source 112 may be configured to distribute light in aspacious manner to an ambient of an area/room in which apparatus 100 isarranged. In addition, germicidal light source 102 and visible lightsource 112 may be configured within the apparatuses described herein todistribute light to surfaces within a room or area that are greater than1.0 meter or even 2.0 or 3.0 meters from apparatus 100. In specificembodiments, germicidal light source 102 and visible light source 112may be configured to have a substantially similar spacial lightdispersement patterns. The light sources may be of any shape, size, orconfiguration in which to achieve such objectives. In specificembodiments, germicidal light source 10 and visible light source 112 mayeach be arranged lengthwise perpendicular to a horizontal plane of asupport structure of an apparatus as shown in FIG. 8.

Other features which may facilitate or enhance disinfection within aroom or area, particularly at distances 1.0, 2.0 or 3.0 meters fromapparatus 100, may be included in apparatus 100. Several examples aredescribed above in regard to FIGS. 1-3 and are not reiterated for thesake of brevity. Furthermore, apparatus 100 may include any of thefeatures described in reference to apparatuses described in reference toFIGS. 1-3, including but not limited to energy storage element/s 26,trigger voltage circuitry 28, power circuitry 30, pulse durationcircuitry 32, program instructions 34, processor 36, optional battery38, remote user interface 40, power cord 42, wheels 44, occupancy sensor46, a user interface on the apparatus (in addition or alternative toremote user interface 40), a handle to aid in portability of theapparatus, a power socket inlet (in addition or alternative to powercord 42) and/or additional sensors, such as additional occupancy sensorsand light sensors. Some of such features are not shown in apparatus 100to simplify the drawing in FIG. 9. Furthermore, some of such featuresare not described in reference to apparatus 100 for the sake of brevity.

As shown in FIG. 8, apparatus 100 may include power supply circuitry 26,pulse circuitry 108, program instructions 28, processor 30, battery 32,remote user interface 34, and occupancy sensor 48. In general, powersupply circuitry 26 is configured to supply power to each of lightsources 102 and 112 for operation thereof and pulse circuitry isconfigured to facilitate pulses of light at germicidal light source 102and possibly at visible light source 112, depending on whether lightfrom visible light source is to be emitted in recurrent pulses orcontinuously. In cases in which visible light source 102 is operated togenerate visible light continuously, the visible light may serve tosubstantially mask the visible light generated by the germicidal lightsource. In contrast, in cases in which visible light source 102 isoperated to generate recurrent pulses of visible light, the pulses ofvisible light from the visible light source may be projected betweenprojections of light from the germicidal light source such that theprojections of visible light from the two light sources produces acollective stream of visible light pulsed at a frequency greater than 60Hz minimizing seizure inducement. In such cases, germicidal light sourceand the visible light source are pulsed at the same frequency but with aphase difference relative to each other. The pulse durations of thegermicidal light source and the visible light source may be the same ordifferent.

FIG. 9 illustrates a diagram of the two operational options ofgenerating light at each of light sources 102 and 112 with respect toeach other. In particular, FIG. 9 shows block 120 denoting that pulse oflight are generated at a germicidal light source. In addition, FIG. 9shows block 122 denoting that light generated at a visible light sourcedistinct from the germicidal light source is generated eithercontinuously or is pulsed. Moreover, FIG. 9 shows block 124 denotingthat the generation of light from the two light sources is governed suchthat projections of visible light from the visible light source andprojections of visible light from the germicidal light source produce acontinuous stream of visible light or a collective stream of visiblelight pulsed at a frequency greater than 60 Hz.

As noted above, an optical filter configured to attenuate a majority orall visible light generated from a germicidal light source may be usedto mask the generation of visible light from the germicidal lightsource. It is noted that the use of such an optical filter is notlimited to embodiments in which the germicidal light source is pulsed ata frequency between 3 Hz and 50 Hz. In particular, any of theapparatuses described herein may include an optical filter configured toattenuate a majority or all visible light generated from the germicidallight source, regardless of the pulse frequency of light generatedtherefrom. It is noted, however, that an optical filter configured toattenuate visible light generally reduces the germicidal efficacy ofroom disinfection apparatuses, particularly at distances at 1, 2 and 3meters away from a germicidal light source of an apparatus. Thus, insome cases, it may be advantageous to omit an optical filter forattenuating visible light in the apparatuses described herein.

It will be appreciated to those skilled in the art having the benefit ofthis disclosure that this invention is believed to provide pulsed lightdisinfection systems and methods which trigger a germicidal pulsed lightsource at a frequency greater than 3 Hz. Further modifications andalternative embodiments of various aspects of the invention will beapparent to those skilled in the art in view of this description.Accordingly, this description is to be construed as illustrative onlyand is for the purpose of teaching those skilled in the art the generalmanner of carrying out the invention. It is to be understood that theforms of the invention shown and described herein are to be taken as thepresently preferred embodiments. Elements and materials may besubstituted for those illustrated and described herein, parts andprocesses may be reversed, and certain features of the invention may beutilized independently, all as would be apparent to one skilled in theart after having the benefit of this description of the invention.Changes may be made in the elements described herein without departingfrom the spirit and scope of the invention as described in the followingclaims. The term “approximately” as used herein refers to variations ofup to +/−5% of the stated number.

What is claimed is:
 1. A disinfection apparatus, comprising: agermicidal pulsed light source arranged within the disinfectionapparatus such that germicidal light generated from the germicidalpulsed light source is projected exterior to the disinfection apparatus;trigger voltage circuitry for applying a trigger voltage to thegermicidal pulsed light source at a set frequency greater thanapproximately 3 Hz; power supply circuitry; one or more electricalcharge storage devices coupled to the power supply circuitry and to thegermicidal pulsed light source; pulse duration circuitry coupled betweenthe one or more electrical charge storage devices and the germicidalpulsed light source; an occupancy sensor for determining presence of anindividual in a region extending at least 1.0 meter from thedisinfection apparatus; a processor; and program instructions executableby the processor for inhibiting and terminating the generation of lightfrom the germicidal pulsed light source upon the occupancy sensordetecting presence of an individual.
 2. The disinfection apparatus ofclaim 1, wherein the one or more electrical charge storage devices andthe pulse duration circuitry are configured to discharge a set amount ofstored energy in a set amount of time such that an energy flux ofultraviolet light in the wavelength range between 200 nm and 320 nmgenerated at the germicidal pulsed light source is between approximately20 J/m² and approximately 1500 J/m².
 3. The disinfection apparatus ofclaim 1, wherein the one or more electrical charge storage devices andthe pulse duration circuitry are configured to discharge a set amount ofstored energy in a set amount of time such that a power flux ofultraviolet light in the wavelength range between 200 nm and 320 nmgenerated at the germicidal pulsed light source is between approximately0.8 MW/m² and approximately 5.0 MW/m².
 4. The disinfection apparatus ofclaim 1, wherein the set frequency is a frequency between approximately3 Hz and approximately 60 Hz.
 5. The disinfection apparatus of claim 1,wherein the set frequency is a frequency greater than approximately 60Hz.
 6. The disinfection apparatus of claim 1, wherein the programinstructions are further executable by the processor for receiving dataregarding the characteristics of a space in which the disinfectionapparatus is to be operated.
 7. The disinfection apparatus of claim 1,wherein the germicidal pulsed light source is a polychromatic germicidallight source.
 8. The disinfection apparatus of claim 1, wherein thegermicidal pulsed light source has an exterior surface area betweenapproximately 50 cm² and approximately 250 cm².
 9. The disinfectionapparatus of claim 1, further comprising a housing surrounding thegermicidal pulsed light source, wherein a sidewall of the housing istransparent to ultraviolet light, and wherein the germicidal pulsedlight source and the housing are arranged in the disinfection apparatussuch that ultraviolet light emitted from the germicidal pulsed lightsource and transmitted through the housing is projected exterior to thedisinfection apparatus.
 10. A disinfection apparatus, comprising: agermicidal pulsed light source arranged within the disinfectionapparatus such that germicidal light generated from the germicidalpulsed light source is projected exterior to the disinfection apparatus;trigger voltage circuitry for applying a trigger voltage to thegermicidal pulsed light source at a set frequency greater thanapproximately 3 Hz; power supply circuitry; one or more electricalcharge storage devices coupled to the power supply circuitry and to thegermicidal pulsed light source; pulse duration circuitry coupled betweenthe one or more electrical charge storage devices and the germicidalpulsed light source; and wheels to affect portability of thedisinfection apparatus.
 11. The disinfection apparatus of claim 10,wherein the one or more electrical charge storage devices and the pulseduration circuitry are configured to discharge a set amount of storedenergy in a set amount of time such that an energy flux of ultravioletlight in the wavelength range between 200 nm and 320 nm generated at thegermicidal pulsed light source is between approximately 20 J/m² andapproximately 1500 J/m².
 12. The disinfection apparatus of claim 10,wherein the one or more electrical charge storage devices and the pulseduration circuitry are configured to discharge a set amount of storedenergy in a set amount of time such that a power flux of ultravioletlight in the wavelength range between 200 nm and 320 nm generated at thegermicidal pulsed light source is between approximately 0.8 MW/m² andapproximately 5.0 MW/m².
 13. The disinfection apparatus of claim 10,wherein the set frequency is a frequency between approximately 3 Hz andapproximately 60 Hz.
 14. The disinfection apparatus of claim 10, whereinthe set frequency is a frequency greater than approximately 60 Hz. 15.The disinfection apparatus of claim 10, wherein the germicidal pulsedlight source has an exterior surface area between approximately 50 cm²and approximately 250 cm².
 16. A disinfection apparatus, comprising: agermicidal pulsed light source arranged within the disinfectionapparatus such that germicidal light generated from the germicidalpulsed light source is projected exterior to the disinfection apparatus;trigger voltage circuitry for applying a trigger voltage to thegermicidal pulsed light source at a set frequency greater thanapproximately 3 Hz; power supply circuitry; one or more electricalcharge storage devices coupled to the power supply circuitry and to thegermicidal pulsed light source; pulse duration circuitry coupled betweenthe one or more electrical charge storage devices and the germicidalpulsed light source; an actuator for moving the germicidal pulsed lightsource relative to a support structure of the disinfection apparatus; aprocessor; and program instructions executable by the processor foractivating the actuator while the germicidal pulsed light source isemitting light.
 17. The disinfection apparatus of claim 16, wherein theone or more electrical charge storage devices and the pulse durationcircuitry are configured to discharge a set amount of stored energy in aset amount of time such that an energy flux of ultraviolet light in thewavelength range between 200 nm and 320 nm generated at the germicidalpulsed light source is between approximately 20 J/m² and approximately1500 J/m².
 18. The disinfection apparatus of claim 16, wherein the oneor more electrical charge storage devices and the pulse durationcircuitry are configured to discharge a set amount of stored energy in aset amount of time such that a power flux of ultraviolet light in thewavelength range between 200 nm and 320 nm generated at the germicidalpulsed light source is between approximately 0.8 MW/m² and approximately5.0 MW/m².
 19. The disinfection apparatus of claim 16, wherein the setfrequency is a frequency between approximately 3 Hz and approximately 50Hz.
 20. The disinfection apparatus of claim 16, wherein the setfrequency is a frequency greater than approximately 60 Hz.